Rotary pump and motor hydraulic transmission



De 2 1 J. H. DAMERON ROTARY PUMP AND MOTOR HYDRAULIC TRANSMISSION FiledApril 12. 1947 I v 2 Sheets-Sheet l Willi INVENTOR. Jom/Yflma 01V 2663,] Dec. 22, 1953 J. H. DAMERON 2W ROTARY PUMP AND MOTOR HYDRAULICTRANSMISSION Filed April 12. 1947 2 Sheets-Sheet 2 41 E 4 a: 5a 7 45 28,29 and 33 in which are disposed the pump gears. The recess 29 receivesthe pump driving gear 3| while the recesses 28 and 39 respectivelyrecesses 28, 29 and 30 have their respective gears receive the pumpdriven gears 32 and 33. The recesses 28, 29 and 39 have their respectivegears 32, 3| and 33 each provided with a close fit for their perimetersthereby, as will be clear, providing a divider between the intake sideand the exhaust or pressure side of the pump chambers.

The pump driving gear 3| is keyed or otherwise secured to the inner endof the driving shaft l3 and which keys are indicated as splines at 34 inFigs. 3 and 4, and wherefor the pump driving gear rotates with thedriving shaft I8. The pump idler gears 32 and 33 are each, respectively,rotatably mounted on a bolt 35 and 36 which passes through alignedapertures in the pump body 29 and motor 2| and finally through aperturesin the motor closure plate 23 to receive nuts, one of which, bolt 35 forexample, is illustrated in Fig. 7 with its nut indicated by referencenumeral 35. In other words the pump idler gears 32 and 33 are rotated oncertain of the bolts that serve the dual purpose of securing thehydraulic transmission members to one another.

The device as illustrated in the drawing contemplates the driving shaftIB being rotated in a clockwise direction for correspondingly rotatingthe pump driving gear 3|. This results in the pump idler gears rotatingin a counterclockwise direction. On one side of the idler gear 32 therecess 28 is enlarged as at 31 to form a duct and which enlarged recess31 terminates in a port 38 extending through the pump body 2!) towardthe motor body 2|. It will be noted that the enlarged recess 31 has itsends defined by a portion of each recess 28 and 29 which, respectively,closely engages the periphery of the idler gear 32 and the driving gear3|. The recess 30 is provided on its opposite hand from that of recess28, as seen in Fig. 4, with an enlarged duct portion 39 which terminatesat its one end in a port 40 and which port 40 similar to the port 38 isformed through the pump body 20 toward the motor body 2|. It will benoted that the enlarged recess 39, similar to the recess 31, has itsends defined by the portions of recesses 29 and 33 which closely engagetheir respective pump driving gear 3| and pump idler gear 33.

The pump body recesses 28 and 29 on the sides opposite of the pump idlergear 32 and pump driving gear 3| from the side in which the enlargedrecess 3'! is formed are likewise enlarged as at 4| and 42. Theseenlarged recesses 4| and 42 form the supply duct for the pump gears 3|and 32 and have connected therewith a supply port 43 which has its otherend terminating in the discharge side of the hydraulic motor as willlater be made clear and for which reasons the port 43 extends throughthe pump body 29 to the motor body. The pump body recesses 29 and- 30are likewise, on the sides of pump gears 3! and 33 opposite from theside of the enlarged recess 39, provided with enlarged ducts 44 and 45.The said ducts 44 and 45 terminate in a supply port 46 which, similar tothe port 43, has its other end at the outlet of the hydraulic motor andtherefore extends through the pump body 23 toward the motor body 2|.

As will be seen in Fig. 3 the pump body 29 has an inner surface. 41which is in face contact with a similar inner surface 48 of the motorbody 2|. The motor body 2| is provided in its face opposite to itscontacting face 48, see Fig. 6, with a plurality of recesses 49, 58, 5|and 52 in each of which is disposed a motor idler gear 53, 54-, 55 and55. Substantially centrally of the motor body 2! is a recess 51 whichbreaks into each of the recesses 49 to 52 at equally spaced points onthe perimeter of therecess 51 which recess 57 receives the motor drivengear 58. The motor driven gear 58 has simultaneous meshing engagementwith the motor idler gears 53 to 56 at the points where their recessesare broken into by the recess of the motor driven gear 58.

The motor driven gear 58 is suitably keyed to the imier end of thedriven shaft l5 and which keying conveniently takes the form of splines59 at the inner end of the driven shaft |5 to be received incorresponding key ways in the motor driven gear 58. The motor idlergears 53 to 56 are each, similar to the pump idler gears 32 and 33rotatably mounted on a bolt 60, 6|, 62 and 53 each of which bolts passesthrough aligned perforations in the motor closure plate 23 and motorbody member 2| to have their threaded ends suitably screwed in threadedapertures in the pump body member 2|). From this it will be seen thatbolts 59 to 63, similar to the bolts 35 and 35, serve a dual purpose ofsupporting the motor idler gears and effect the securing of the body orhousing members and closure plates of the transmission device to oneanother to provide a unitarily operating structure.

Formed in the motor body member 2| are a pair of ducts or ports 64 and55 which extend through said motor body member toward the pump bodymember and communicate with the port 33 and the inner ends of whichports 54 and 55, respectively communicate with the motor driving gearrecess at points closely adjacent the meshing of said motor driven gear53 with motor idler gears 53 and 55. Likewise the motor body 2! isprovided with a pair of ducts or ports 65 and 6'5 which communicate withthe pump port 43. The inner ends of the said ducts or ports 55 and lil,respectively, communicate with the motor driven gear recess 51 at pointsadjacent the intermeshing of said motor driven gear 58 and the motoridler gears 53 and 54. By this construction the hydraulic medium underpressure flowing from the said ports 64 to 57, inclusive, acts on theteeth of the motor driven gear and the motor idler gears and tend torotate said motor idler gears 53 to 53 which in turn drive the motordriven gear 53 in a clockwise direction and thereby rotate the drivenshaft l5 in a clockwise direction and which isthe direction the drivingshaft I3 is being actuated.

Communicating with the motor driven gear recess 5'! and each of themotor idler gear recesses 39 to 52 inclusive, are outlet ports 53, 39,'53 and H. The outlet ports 68 and 53 respectively connect with the port53 for thereby supplying the hydraulic medium to the pump gears 35 and32. The outlet ports 'iii and ii of the motor likewise respectively,communicate with the inlet port 43 that supplies the hydraulic medium tothe pump gears 35 and 33.

From the foregoing it will be noted that rotation of the pump gearsdischarges a hydraulic medium under pressure into the enlarged recesses3'5 and 39 of the pump which in turn is passed through the ports 38 and45 to, respectively, motor ports 34-455 and 66-61 for thereby rotatingthe motor driven gear 58. The hydraulic attend? medium after-acting oh"the meter unve l gear 58 is discharged through "the ports 68 tell,inclu's'ive, to the ports W3 nuns, which, through the enlarged recesses'41 em n-and uanu 45 supply the pump gears 'with' the-hydraulic me diumto be -reci'rcula'ted under pressure.

From the foregoing it will be noted that the hydraulic transmissionincludes a completely closed circuit for a hydraulic medium and whichmedium should be "of the "non-elastic type-such as oil. Order to supplythe 'said'hydraulic medium to the transmission device, the housing "1.0-is provided with a filler opening 12 normally closed by 'a-plugfD-hediller opening '12 enables the housing l0 to be completely filledwith the said'hydraulic 'm'ediumi'and ihforderrtoifill the various portsand ducts .of thectransmission mechanism the .pun'ip body gal- 1'sprovided with openings 14 and "Mf,.'respectively,rnormallycclosed byplugs or the like 15 and15'. Theopening :14 supplies the pressure side.of the system "while the opening 14 supplies the return side thereof.

It is believed that the normal op'eration 'ofthe transmission device. isunderstood from :the foregoing description. In .use'a'nd as stated abovethe housing In is held stationary and acts asthe support for thetransmission device. In "what may be termed low gear or with thegreatest amount of torque on the driven'shaft lfithe parts operatesubstantially asabove set forth, namely, a'motive force, such asderivedfrom a'gasoline engine, isapplied to the driving 'shaft 18 forrotating thepump gears which cause "a circulation of the hydraulicmedium, under pressure,

through the transmission device for inturn rotating the drivenshaft. Themaximum torque on the driven shaftrlt may-be establishedin'the ratio offour tooneto the'torqueon thedrive shaft as will later bemadeclear. Withthis condition the RP. M. of the driven shaftiszsubstantially one fourthof that of 'the drive-shaft l8.

In order to establish this condition the following specifications forthe various-gears were employed:

In the pump the driving gear 3! had a radius of 1.5 inches, a-face widthof -,1'.39 inches and-a wholetooth depth of -:3595 inch, while each=pump idler gears had a radius of 1.- 584- inches,a face width of 1.39inches and a whole tooth depth of ,3595 inchresulting in apressuresurface on the two pump idler gears ofapproximately one squareinch. Themotor driven gear ea ned a radius of 225 inches, a facewidth-of1.855 inches and a whole tooth depth .-of .3595 inch, -while-each-oi themotoridler gears hadia radiusof 1834inch, a face idth-of1,855inches-anda-whole tooth depth of .3595inchtherebymresentingaspressure surface on the fourmotor'idlersgearsillustrated in the drawing of-2.6678 inches. The oilpressure developed by one horsepower at 3000 R. P. M. :gave-6600inchtpounds'per-second per'50 revolutions or-l32inch-pounds perrevolution which expressed in aformulareads:

6601) in. lbs. sec. 50 R, PIS.

Since the-pump driving gear is$3- inches in diameter it has acircumferenceof'9l42 inches and will therefore develop very slightlymore Ethan 14 pounds pressure Tper rhorse" poweriper square inch, andwhich expressed as a formula "reads:

14.01 lbs. '(pie'ssur'e er'h. "P. persqiin,

into the following-form: g i Si'n'ce the"m'un'p- *driving 'gear -na' s aradius bi 1:5". and a total tooth so? 1 :sq. and has 20 geazrteeth,seachitoothneliveredxone twentiethiofithe tbtal pressuredevelopedfinionefrevolution which resultszini aipressure of 454 lbs.ipe'r horsepower, a'nd expressed :as a :formula :rea'ds:

As illustratedin the drawing itheihydraulic pressure on thepumpidlerlgears is exerted atlrig'ht angles to the tooth .radius .-.oneach Ltooth just before it emerges fromitsmecess, .as'shown on Fig. 4.Since the idlers are 'frely rotatable on their axles'thishydraulicfforce is also exerted as a mechanical forceagainstlthergear teeth of the driving gear, .theidle'r ailesactingzas afulcrum. The resultant of .these 'two ..'forces acting onfthe axles-ofthe-idlers 'isgexerted on .the pump assembly, the component of which.forces, acting at rightv anglesi'to Qthera'diusbf thapump body,provides .afmomentwhich tends torotate the pump end of the-assembly inablockwise direction.

'In'the motor end 615 ",the*ias'sembly,t'a similar but oppositecondition exists. The hydraulic force iseXerted on'-ea ch-' motor idlergear tooth at right angles to -gear radius as it --enters its closelyfitting recess 49 to 52 =-as shownon Fig. 6. This force results in-anequal -mechanical force being exerted against-the teeth of the motordriven central-gear. 'The resultant of the forces acting through theaxles fulcrums of the motor idler gears is exerted on the motorassembly, the 'compo'n'ento'f which providese moment which, acting atright -angles-to the radius of the motor bod-y, tends-"to rotate the 1assembly in a counterclockwisedirection. .HSince'the pump end and motorend ofthe mot'or pump -assembly have been shown t'o be join'ed by boltsinto :an integral unit, it can be seen -that the two moments described,'acting' simultaneously:as a re-- sult of the same hydraulicpressureycancel each. other and cannot result in'lrotation' of -thetransmission assembly as l'ong-as these two :moments:

areequal' and opposite. Ji in-analysis.of the forces shows that-the'a-bove moments are equal and. opposite when the' lo'ad i's at "themaximum torque that can bedelivered. This -results from the specificdimensions above set forth in :a stationary condition of thepump-motorassembly and a power 'delivery of 'a 4 to 1 ratio: resulting entirelyfrom the pumpin'g actionpf the parts. Power delivery o'n 'the motordriven gear "is .a result of the actionon' -the motoridler gear teethwhich receive their power from ithe 1 :hydraulic pressure contained *inlth'e Lpressure side ciof ithe circuit betweenthe pumpand' 'the motor..This pressure "is' the 1 result. of Jthe power delivered. .by thepumpandtheresistancexafiered through:the motor. With niconstant isource iofspower, the

pressure can then be said to be directly pro; portional to the load onthe driven shaft.

The moment exerted on the motor-pump assembly by the motor idler gearsthrough their axles in a counter-clockwise direction, is the result ofthe hydraulic pressure. Since the pressure is directly proportional tothe load, so is the counter-clockwise force directly proportional to theload. Therefore, as the load is increased on the driven shaft, thecounter-clockwise moment approaches a balance with the clockwise moment,reducing theforward or clockwise speed of the transmission assembly andthereby bringing about an increase of pumping action with an increase oftorque on the driven shaft until the maximum is reached where a perfectbalance of moments exists, there is no forward motion of the pump-motorassembly, and power is delivered by a full pumping action at the maximumratio,

The foregoing dimensions and formulas are given by way of examples andare not to be construed as limiting the invention to the said exactdimensions and angles.

As the torque on the driven shaft l lessens the said shaft tends tospeed up in R. P. M. and at the same time the torque in the motor inexcess of that required to rotate the driven shaft l5 must be used ordissipated, The reverse reaction on the housing'is reduced and overcomeby the forward reaction. This excess torque is dissipated by reacting onthe transmission members themselves thereby effecting a forward rotationand increase in R. P. M. on the driven shaft and these conditionscontinue until there is established a balance of torque between thatapplied to the driving shaft and that required to turn the driven shaftwhen added to that required for rotating the transmission members.

From the foregoing it will now be apparent that there has been provideda transmission mechanism that accomplishes the objects initially setforth.

What is claimed is:

1. In a hydraulic transmission the combina tion of a combined hydraulicpump-motor housing forming the reaction member for a hydraulic pump atone end thereof and the reaction member for a hydraulic motor at theother end thereof, said pump-motor housing including a pump expansionchambercontaining a high pressure area and a low pressure area separatedfrom one another by a driving gear and a pump idler gear, saidpump-motorhousing including a hydraulic motor expansion chambercontaining a high pressure area and a low pressure area separated by adriven gear anda motor idler gear, said high pressure areas of the pumpand motor expansion chambers being, respectively,ron opposite hands ofits driving and driven gears, as viewed from an end thereof, so that thereactive forces on the pump-motor housing are opposed to one another,said pump driving andidler gears being formed to dimensions differentfrom the dimensions of the motor driven and idler gears so'that there isa difference in fluid capacities of the pump and motor and a torqueratio between them greater than one to one, a driving shaft rotatablymounted in said pump-"notor housing fixed to said pump driving gear, adriven shaft rotatably mounted in said pump-motor housing fixed to saidmotor driven gear, a closed fluid circuit between the high pressureareas of the pump and motor, a closed fluid circuit between the lowpres'sureareasof the pump and motor,

and means mounting the pump-motor housing, the drive shaft and thedriven shaft for independent and unitary rotation so that said pumpmotorhousing may rotate as determined by the difference in reactive torque onthe reactive pump-motor housing and which rotation increases in rate asthe torque between the pump and motor approaches a torque ratio of oneto one.

2. In a hydraulic transmission the combination of a combined hydraulicpump-motor housing forming the reaction member for a hydraulic pump atone end thereof and the reaction member for a hydraulic motor at theother end thereof, said pump-motor housing including a pump expansionchamber containing a high pressure area and a low pressure areaseparated from one another by a driving gear and a pump idler gear, saidpump-motor housing including a hydraulic motor expansion chambercontaining a high pressure area and a low pressure area separated by adriven gear and a motor idler gear, said high pressure areas of the pumpand motor expansion chambers being, respectively, on opposite hands ofits driving and driven gears, as viewed from an end thereof, so that thereactive forces on the pump-motor housing are opposed to one another,said pump driving and idler gears being formed to dimensions differentfrom the dimensions of the motor driven and idler gears so that there isa difference in fluid capacities of the pump and motor and a torqueratio between them greater than one to one, a driving shaft rotatablymounted in said pump-motor housing fixed to said pump driving gear, adriven shaft rotatably mounted in said pump-motor housing fixed to saidmotor driven gear, a closed fluid circuit between the high pressureareas of the pump and motor, a closed fluid circuit between the lowpressure areas of the pump and motor, and a stationary casing enclosingthe pump-motor housing and providing bearings therefor so that saidpump-motor housing may freely rotate relative thereto and relative tothe driving and driven shafts as determined by the difference inreactive torque on the reactive pump-motor housing and which rotationincreases in rate as the torque between the pump and motor approaches aone to one ratio. a

3. In a hydraulic transmission the combination of a combined hydraulicpump-motor housing forming the reaction member for a hydraulic pump atone end thereof and the reaction member for a hydraulic motor at theother end there of, said pump-motor housing including a pump expansionchamber containing a high pressure area and a low pressure areaseparated from one another by a driving gear and a pump idler gear, saidpump-motor housing including a hydraulic motor expansion chambercontaining a high pressure area and a low pressure area separated by adriven gear and a motor idler gear, said high pressure areas of the pumpand motor expansion chambers being, respectively, on opposite hands ofits driving and driven gears, as viewed from an end thereof, so that thereactive forces on the pump-motor housing are opposed to one another,said pump driving and idler gears being formed to dimensions differentfrom the dimensions of the motor driven and idler gears so that there isa difference in fluid capacities of the pump and motor and a torqueratio between them greater than one to one, a driving shaft rotatablymounted in said pump-motor housing fixed to said pump driving gear, adriven shaft rotatably 9 mounted in" said pump-motor housing fixed tosaid-1 motor driven gear, said pump-motor house ing having a port formedtherethrough forming a closed fluid circuit between the high pressureareas of the pumpiand motor,'said pump-motor housing having anadditional port formed therethrough, forming a closed fluidcircuit-between the low pressure areas of the pump and. motor, and meansmounting the pump-motor housing, the drive shaft and the driven shaft;forindependent and unitary rotation so that saidpump-motor housing-mayrotate as determinedv by the. difiere ence in reactive "torque on thereactive pump-. motor housing and which rotation increases. inrate asthe torque between the pump and motorapproaches a, torque ratio of onetov one.

4. In a hydraulic transmission the combina-.

tion offa combined: hydraulic pump-motor housing forming the; reaction,member for ahydraulio pump at one end thereoi and the reaction mem-, herfor a hydraulic motor at the other end thereof, said pump-motor housingincluding a pump expansion chamber containing a high pressure. area anda. lowpressure: area-separated from one another-by a driving gear and apump. idler gear,

said pump-motor housing including a hydraulic:

motor expansion chamber containing a high pressure area and alowpressure area. separated by a driven gear-and a motor idler gear,said high pressure areas of the pump; and motor expansion chambersbeing-,7 respectively, on opposite hands of; its driving and; drivengearsas viewed from an end thereof; so, that the reactive forces on thepump-motor housing are opposed to one another, said pump drivirneandidler gears being formed to. dimensions diiierent from the dimensionsof the motor driven and idler gears so, that there is a difierence influid capacities. of the pump and motor and a torque ratio between themgreater than one to. one, a. driving shaft: rotatably mounted in saidpump-motor housing: fixed to, said pump driving gear; a: driven shaftrotatably mounted in said pump-motor housing fixed to said; motor drivengear, said} pump-motor housing having a, port formed therethroughforming a closed fluid circuit between the high pressure areas of thepump and" motor, said: pump-motor housinghaving an additional port;formed therethrough forming; a closed fluid circuit between thevlowpressure areas, of the pump and motor, and a stationary casingenclosing the pump-motor housing and providing bearings, therefor sothat said pump-motorhousing may freely; rotate, relative thereto andrelative to: the driving and driven shafts: as determined bythedifierence reactive torque on the reactive pump-motorhousing andwhich rotation increases, in rate as the torque between. the pump and;motor approaches a one to, one ratio,

5., A hydraulic transmission comprising a drivin shaft and a. drivenshaft, a pumpbody meme beriormizng thereaction member fora hydraulicpump and havinga recess therein for a driving gear and a, plurality ofpump: idler. gears respectively enmeshed at spaced pointscircumferentially on, said driving gear and with said driving ear:secured to the driving shaft, said enmeshed pump dr vin and, idler gearfo min in thepump body member recess on each, side of each idler gear,respectively, a high pressure area and a low pressure area, amotorbodymember forming the reaction member for a hydraulic motor and have.ing formed therein a recess for a driven gear and a. plurality of motoridler gears respectively ens meshed at spaced points circumferentiall-yon said driven gearand with said driven gear secured: to the drivenshaft, said enmeshed motor driven and idler gears I forming in the motorbody recess a high pressure area and a low pressure area respectively onopposite sides or each motor idler gear, said pump driving and idlergears beingformedto dimensions d-ifierent from the dimensions ofthe-motordriven and-idler gears sothat there is a diiierence in fluidcapacities of the pump and motor recesses and a torque ratio between thepump and motor greater than one to one, said pump body memberandsaidmotor bod-y member being arranged in contact with one another andwith a common axis, means secur ing the pump body member-and motorbodymemberto one another with their high pressure areas, respectively onopposite hands of its driving and; driven gears, as viewed from an endthereof, so that-the reactive forces on the pump body meme ber and themotor body member are opposed toone another, a closed fluid circuitbetween thehigh pressure areas of the pump and motor, a closed fluidcircuit between the low pressure areas of the pump and motor, and meansmounting the connected pump and motor body members, the drive shaft andthe driven shaft for independent and unitary rotation so that saidcon--nected pump and motor body members may-rotate as determined by thedifference in reactive torque on the pump body member and the motor bodymember and which rotation increases inrate as the torque between thepump and motor approaches a torque ratio of one to one.

6'. A hydraulictransmission comprising a dPiV-z ing shaft and a drivenshaft, a pump bodymember forming the reaction member for a hydraulicpump and having a recess therein for a driving" gear and a plurality ofpumpidler gears respectively enmeshed at spaced points circumferentiallyonsaid driving gear and with said driving gear secured to the drivingshaft, said en-i meshed pump driving and idler gears forming in the pumpbody member recess on each side of each idlergear; respectively, a highpressure area and a low pressure area, a motor body memberforming thereaction member for a hydraulic motor and having formed therein a recessfor a, driven-- gear and a plurality of motor idler gears respectivelyenmeshed" at spaced points circumferentially on said driven gear andwith said driven gear secured to: the driven shaft, said enmeshed motordriven and idler gears forming in the motor body recess a high pressurearea and a low pressure area, respectively, on opposite sides of' eachmotor idler gear, said pump drive and idler gears being formed todimensions different from the dimensions of-the motordr-iven and idlergears so that there is a difference in fluid capacities of the pump andmotor recesses and a torque ratio between the pump and motorgreater thanone to one, said pump body memher and said motor body: member beingarranged in contact with one another and with a common axis, meanssecuring the pump body member and motor body member to one another withtheir high pressure areas, respectively, on opposite hands of itsdriving and driven gears, as viewed from an end thereof, so that thereactive forces on the pump body member and the motor body member areopposed to. one another, a closed fluid circuit; between the highpressure areas of the pump and motor, a closed fluid circuit between thelow pressure. areas of the pump and motor, and a stationary casingenclosing the ,connected pump; and motor body members: and

providing bearings therefor so that said connected motor and pump bodymembers may freely rotate relative thereto and relative to the drivingand driven shafts as determined by the difierence in reactive torque onthe pump body member and the motor body member and which rotationincreases in rate as the torque between the pump and motor approaches aone to one ratio.

'7. A hydraulic transmission of the class do scribed comprising a pumpbody member forming the reaction member of a hydraulic pump and a motorbody member forming the reaction member of a hydraulic motor, said bodymembers being secured to one another in face contact and with a commonaxis, each of said pump and motor body members having a face other thanthat in contact, the pump body member having formed in its second facerecesses for a pump driving gear and a plurality of pump idler gearsrespectively enmeshed at points circumferentially of the driving gear,said enmeshed pump driving and idler gears forming in each recess a highpressure area on one side of each idler gear and a low pressure area onthe opposite side of each idler gear, a closure plate on the second faceof the pump body member for closing the recesses, a driving shaftrotatably mounted in said pump recesses closure plate having securedthereto the pump driving gear, the motor body member having formed inits second face recesses for a motor driven gear and a plurality ofmotor idler gears enmeshed at points circumferentially of the motordriven gear, said enmeshed motor driven idler gears forming in eachrecess on one side of each motor idler gear a high pressure area and onthe opposite side of each motor idler gear a low pressure area, a motorrecesses closure plate on the motor body member second face, a drivenshaft rotatably supported by the motor recesses closure plate and havingsecured thereto the motor driven gear, said pump driving and idler gearsbeing formed to dimensions different from the dimensions of the motordriven and idler gears so that there is a difference in fluid capacitiesof the pump and motor and a torque ratio between them greater than oneto one, said securing of the pump body member and the motor body memberbeing such that their high pressure areas are, respectively, on oppositehands of the driving and driven gears, as viewed from an end thereof, sothat the reactive forces on the pump body member and motor body memberare opposed to one another, a closed fluid circuit between the highpressure areas of the pump and motor, a closed fluid circuit between thelow pressure areas of the pump and motor, and means mounting theconnected pump and motor body members, the drive shaft and driven shaftfor independent and unitary rotation so that said connected pump andmotor body members may rotate as determined by the difference inreactive torque on the pump body member and the motor body member andwhich rotation increases in rate as the torque between the pump andmotor approaches a torque ratio of one to one.

8. A hydraulic transmission of the class described comprising a pumpbody member forming the reaction member of a hydraulic pump and a motorbody member forming the reaction member of a hydraulic motor, said bodymembers being secured to one another in face contact and with a commonaxis, each of said pump and motor body members having a face other thanthat in contact, the pump body member having formed in its second facerecesses for a pump driving gear and a plurality of pump idler gearsrespectively enmeshed at points circumferentially of the driving gear,said enmeshed pump driving and idler gears forming in each recess a highpressure area on one side of each idler gear and a low pressure area onthe opposite side of each idler gear, a closure plate on the second faceof the pump body member for closing the recesses, a driving shaftrotatably mounted in said pump recesses closure plate having securedthereto the pump driving gear, the motor body member having formed inits second face recesses for a motor driven gear and a plurality ofmotor idler gears enmeshed at points circumferentially of the motordriven gear, said enmeshed motor driven and idler gears forming in eachrecess on one side of each motor idler gear a high pressure area and onthe opposite side of each motor idler gear a low pressure area,

. a motor recesses closure plate on the motor body member second face, adriven shaft rotatably supported by the motor recesses closure plate andhaving secured thereto the motor driven gear, said pump driving andidler gears being formed -to dimensions different from the dimensions ofthe motor driven and idler gears so that there is a difference in fluidcapacities of the pump and motor and a torque ratio between them greaterthan one to one, said securing of the pump body member and the motorbody member being such that their high pressure areas are, respectively,on opposite hands of the driving and driven gears, as viewed from an endthereof, so that the reactive forces on the pump body member and motorbody member are opposed to one another, ports formed in the pump andbody members from the high pressure areas of their respective recessesthrough their contact ing faces in alignment with one another to form aclosed fluid circuit between the high pressure areas of the pump andmotor, additional ports formed through said pump and motor body membersfrom the low pressure areas of their respective recesses through thecontacting faces therei of in alignment with one another to form aclosed fluid circuit between the low pressure areas of the pump andmotor, and means mounting the connected pump and motor body members, thedrive shaft and the driven shaft for independent 2 and unitary rotationso that said connected pump and body members may rotate as determined bythe difference in reactive torque on the pump body member and the motorbody member and which rotation'increases in rate as 'the torque betweenthe pump and motor approaches a torque ratio of one to one.

9. A hydraulic transmission of the class described comprising a pumpbody member forming the reaction member of a hydraulic pump and a motorbody member forming the reaction member of a hydraulic motor, said bodymembers being secured to one another in face contact and with a commonaxis, each of said pump and motor body members having a face other thanthat in contact, the pump body member having formed in its second facerecess for a pump driving gear and a plurality of pump idler gearsrespectively enmeshed at points circumferentially of the driving gear,said enmeshed pump driving and idler gears forming in each recess a highpressure area on one side of each for closing the recesses, a. drivingshaft rotatably' 13 mounted in said pump recesses closure plate havingsecured thereto the pump driving gear, the motor body member havingformed in its second face recesses for a motor driven gear and aplurality of motor idler gears enmeshed at points circumferentially ofthe motor driven gear, said enmeshed motor driven and idler gearsforming on one side of each motor idler gear a high pressure area and onthe opposite side of each motor idler gear a low pressure area, a motorrecesses closure plate onthe motor body member second face, a drivenshaft rotatably supported by the motor recesses closure plate and havingsecured thereto the motor driven gear, said pump driving and idler gearsbeing formed to dimensions different from the dimensions of the motordriven and idler gears so that there is a difference in fluid capacitiesof thepump and motor and a torque ratio between them greater than one toone, said securing of the pump body member and the motor body memberbeing such that their high pressure areas are, respectively, on oppositehands of the driving and driven gears, as viewed from an end thereof, sothat the reactive forces on the pump body member and motor body memberare opposed to one another, ports formed in the pump and body membersfrom the high pressure areas of their respective recesses through theircontacting faces in alignment with one another to form a closed fluidcircuit between the high pressure areas of the pump and motor,additional ports formed through said pump and motor body members fromthe low pressure areas of their respective recesses through thecontacting faces thereof in alignment with one another to form a closedfluid circuit between the low pressure areas of the pump and motor, abearing boss outwardly projecting from each of the pump body memberrecesses and motor body member recesses closure plates, and a stationarycasing enclosing the connected pump and motor body members and providingbearings for their closure plates bearing bosses so that said connectedpump and motor body members may freely rotate relative thereto andrelative to the driving and driven shafts as determined by thedifference in reactive torque on the pump body member and the motor bodymember and which rotation increases in rate as the torque between thepump and motor approaches a. one to one ratio.

JOHN H. DAMERON.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,080,282 Kellogg Dec. 2, 1913 1,243,640 Story Oct. 16, 19171,647,621 Hawley Nov. 1, 1927 1,914,622 Smith June 20, 1933 1,998,922Chamberlain et a1. Apr. 23, 1935 2,198,891 Thoma Apr. 30, 1940 2,323,926McGill July 13, 1943

